Adverse drug reactions attributed to generic substitution of antiretroviral medications among HIV treatment and pre-exposure prophylaxis clients in British Columbia, Canada.

BACKGROUND: In British Columbia, antiretrovirals (ARVs) for HIV treatment (HIV-Tx) and pre-exposure prophylaxis (PrEP) are free-of-charge through publicly-funded Drug Treatment Programs (DTPs). When available, less costly generics are substituted for brand-name ARVs. We describe the incidence and type of product substitution issue (PSI) adverse drug reactions (ADRs) attributed to generic ARVs. METHODS: Cohorts included DTP clients ≥19 years who received generic ARVs for HIV-Tx (abacavir-lamivudine, emtricitabine-tenofovir DF, efavirenz-emtricitabine-tenofovir DF, atazanavir or darunavir between 01 Jun 2017 and 30 Jun 2022) or PrEP (emtricitabine-tenofovir DF, 01 Apr 2018 to 30 Jun 2022). Demographic, ARV and ADR data were extracted from DTP databases and summarized by descriptive statistics. PSI incidence was calculated for each product during the year following brand-to-generic and generic-to-generic transitions (first-year-post-rollout), and compared between generic versions using generalized estimating equations. For context, incidence of any ARV product-related ADR was calculated in the same 1-year periods. RESULTS: During first-year-post-rollout periods, 5339 HIV-Tx (83% male, median age 52 years) and 8095 PrEP (99% male, median 33 years) clients received generic ARVs, and reported 78 and 23 generic PSIs, respectively. PSI incidence was <1% for most generic ARVs, with mild-moderate symptoms including gastrointestinal upset, headache, dizziness, fatigue/malaise and skin rash. In HIV-Tx clients, the efavirenz-containing product had higher PSI incidence than other ARVs (2.2%, p = .004), due to more neuropsychiatric adverse reactions. Any ADR incidence was stable across measurement periods, and generic PSIs represented less than one third of all product-related ADRs. CONCLUSIONS: Generic substitution of antiretrovirals for HIV-Tx and PrEP was well tolerated, with ≤2% incidence of mild-moderate PSI ADRs.

Tobacco smoking and HIV-related immunologic and virologic response among individuals of the Canadian HIV Observational Cohort (CANOC).

We assessed the relationship between tobacco smoking and immunologic and virologic response among people living with HIV (PLWH) initiating combination antiretroviral therapy (cART) in the Canadian HIV Observational Cohort (CANOC). Positive immunologic and virologic response, respectively, were defined as ≥50 cells/mm3 CD4 count increase (CD4+) and viral suppression ≤50 copies/mL (VL+) within 6 months of cART initiation. Using multinomial regression, we examined the relationship between smoking, immunologic, and virologic response category. Model A adjusted for birth sex, baseline age, enrolling province, and era of cohort entry; models B and C further adjusted for neighbourhood level material deprivation and history of injection drug use (IDU), respectively. Among 4267 individuals (32.7%) with smoking status data, concordant positive (CD4+/VL+) response was achieved by 64.2% never, 66.9% former, and 59.4% current smokers. In the unadjusted analysis, current smoking was significantly associated with concordant negative response (odds ratio [OR] 1.85, 95% confidence interval [CI] 1.40-2.45). Similarly, models A and B showed an increased odds of concordant negative response in current smokers (adjusted OR [aOR] 1.78, 95% CI 1.32-2.39 and 1.74, 95% CI 1.29-2.34, respectively). The association between current smoking and concordant negative response was no longer significant in model C (aOR 1.18, 95%CI 0.85-1.65).

Estimation of time of HIV seroconversion using a modified CD4 depletion model.

INTRODUCTION: Several methods have been proposed to estimate the time of HIV seroconversion, including those based on CD4 cell depletion models. However, previous models have failed to consider the heterogeneity that exists in CD4 trajectories among different sub-populations. Our objective was to estimate the time from HIV seroconversion relative to the HIV diagnosis date in a population-based cohort of people living with HIV (PLWH) in the province of British Columbia, Canada. METHODS: We used linked administrative and clinical data from the British Columbia Seek and Treat for Optimal Prevention of HIV/AIDS (STOP HIV/AIDS) cohort, which contains longitudinal individual-level data on all PLWH ever diagnosed in the province. Eligible participants were aged ≥18 years and diagnosed with HIV between 1989 and 2013. The outcome was pre-antiretroviral treatment CD4 cell count measurements assessed every six months. Models were stratified by age and stage of HIV infection at diagnosis. Several explanatory variables were considered including longitudinal viral load measurements. Longitudinal CD4, square root transformed, was modeled via a non-linear mixed effects model; time was modeled using an exponential decay function. We assumed a Gaussian distribution (identity link), an AR(1) correlation structure, and a random intercept and slope for the longitudinal viral load measurements. Due to the population variation in CD4 count among uninfected individuals, we assumed 500 to 1500 cells/mm3 as the normal range when estimating the time of HIV seroconversion. RESULTS: Longitudinal data on 1,253 individuals were analysed: 80% male, 33% White, and the median age at diagnosis was 38 years (25th-75th percentile [Q1-Q3], 31 to 45). CD4 decay differed by stage of infection at diagnosis and age, with those ≥50 years in Stages 1 and 2 experiencing a faster decline in CD4 over time. The median duration of infection from seroconversion until HIV diagnosis was 6.9 (Q1-Q3, 3.9 to 10.1) years. CONCLUSIONS: Considering the heterogeneity that exists in individual CD4 cell trajectories in a population, we presented a methodology that only relies on routinely collected HIV-related data, which can be further extended to estimate other epidemic measures.

Excess burden of age-associated comorbidities among people living with HIV in British Columbia, Canada: a population-based cohort study.

OBJECTIVES: As people living with HIV (PLWH) live longer, morbidity and mortality from non-AIDS comorbidities have emerged as major concerns. Our objective was to compare prevalence trends and age at diagnosis of nine chronic age-associated comorbidities between individuals living with and without HIV. DESIGN AND SETTING: This population-based cohort study used longitudinal cohort data from all diagnosed antiretroviral-treated PLWH and 1:4 age-sex-matched HIV-negative individuals in British Columbia, Canada. PARTICIPANTS: The study included 8031 antiretroviral-treated PLWH and 32 124 HIV-negative controls (median age 40 years, 82% men). Eligible participants were ≥19 years old and followed for ≥1 year during 2000 to 2012. PRIMARY AND SECONDARY OUTCOME MEASURES: The presence of non-AIDS-defining cancers, diabetes, osteoarthritis, hypertension, Alzheimer's and/or non-HIV-related dementia, cardiovascular, kidney, liver and lung diseases were identified from provincial administrative databases. Beta regression assessed annual age-sex-standardised prevalence trends and Kruskal-Wallis tests compared the age at diagnosis of comorbidities stratified by rate of healthcare encounters. RESULTS: Across study period, the prevalence of all chronic age-associated comorbidities, except hypertension, were higher among PLWH compared with their community-based HIV-negative counterparts; as much as 10 times higher for liver diseases (25.3% vs 2.1%, p value<0.0001). On stratification by healthcare encounter rates, PLWH experienced most chronic age-associated significantly earlier than HIV-negative controls, as early as 21 years earlier for Alzheimer's and/or dementia. CONCLUSIONS: PLWH experienced higher prevalence and earlier age at diagnosis of non-AIDS comorbidities than their HIV-negative controls. These results stress the need for optimised screening for comorbidities at earlier ages among PLWH, and a comprehensive HIV care model that integrates prevention and treatment of chronic age-associated conditions. Additionally, the robust methodology developed in this study, which addresses concerns on the use of administrative health data to measure prevalence and incidence, is reproducible to other settings.